Fix client side crashes in the sync system

src/game.zig

@@ -627,6 +627,11 @@ pub fn update(deltaTime: f64) void { // MARK: update()
 	if (world.?.shouldRestart.load(.acquire)) {
 		restart();
 	}
+	main.sync.client.update() catch |err| {
+		std.log.err("Got error while processing server sync commands: {s}. Disconnecting", .{@errorName(err)});
+		main.exitToMenu();
+		return;
+	};
 
 	physics.calculateVolumeProperties(.client, &Player.volumeProperties, Player.super.pos, Player.outerBoundingBox, physics.playerAirTerminalVelocity);
 	if (Player.isFlying.load(.monotonic)) {

src/network/protocols.zig

@@ -959,11 +959,11 @@ pub const inventory = struct { // MARK: inventory
 	fn clientReceive(_: *Connection, reader: *utils.BinaryReader) !void {
 		const typ = try reader.readInt(u8);
 		if (typ == 0xff) { // Confirmation
-			try main.sync.client.receiveConfirmation(reader);
+			main.sync.client.receiveSyncOperation(.init(.confirmation, reader.remaining));
 		} else if (typ == 0xfe) { // Failure
-			main.sync.client.receiveFailure();
+			main.sync.client.receiveSyncOperation(.init(.failure, &.{}));
 		} else {
-			try main.sync.client.receiveSyncOperation(reader);
+			main.sync.client.receiveSyncOperation(.init(.sync, reader.remaining));
 		}
 	}
 	fn serverReceive(conn: *Connection, reader: *utils.BinaryReader) !void {

src/sync.zig

@@ -27,6 +27,22 @@ pub const Side = enum { client, server };
 pub const client = struct { // MARK: client
 	pub var mutex: main.utils.Mutex = .{};
 	var commands: utils.CircularBufferQueue(Command) = undefined;
+	var syncCommands: main.ListManaged(ClientSyncOperation) = .init(main.globalAllocator);
+	const ClientSyncOperation = struct {
+		const Type = enum { confirmation, failure, sync };
+		typ: Type,
+		data: []const u8,
+
+		pub fn init(typ: Type, data: []const u8) ClientSyncOperation {
+			return .{
+				.typ = typ,
+				.data = main.globalAllocator.dupe(u8, data),
+			};
+		}
+		fn deinit(self: ClientSyncOperation) void {
+			main.globalAllocator.free(self.data);
+		}
+	};
 
 	pub fn init() void {
 		commands = utils.CircularBufferQueue(Command).init(main.globalAllocator, 256);
@@ -35,6 +51,7 @@ pub const client = struct { // MARK: client
 	pub fn deinit() void {
 		reset();
 		commands.deinit();
+		syncCommands.deinit();
 	}
 
 	pub fn reset() void {
@@ -45,6 +62,9 @@ pub const client = struct { // MARK: client
 				std.log.err("Got error while cleaning remaining inventory commands: {s}", .{@errorName(err)});
 			};
 		}
+		while (syncCommands.popOrNull()) |sync| {
+			sync.deinit();
+		}
 		mutex.unlock();
 	}
 
@@ -62,52 +82,55 @@ pub const client = struct { // MARK: client
 		commands.pushBack(cmd);
 	}
 
-	pub fn receiveConfirmation(reader: *BinaryReader) !void {
+	pub fn receiveSyncOperation(sync: ClientSyncOperation) void {
 		mutex.lock();
 		defer mutex.unlock();
-		if (commands.popFront()) |cmd| {
-			try cmd.finalize(main.globalAllocator, .client, reader);
-		} else {
-			std.log.err("Received unexpected confirmation sync. Disconnecting", .{});
-			return error.Invalid;
-		}
+		syncCommands.append(sync);
 	}
 
-	pub fn receiveFailure() void {
+	pub fn update() !void {
 		mutex.lock();
 		defer mutex.unlock();
+		if (syncCommands.items.len == 0) return;
+
 		var tempData: main.List(Command) = .empty;
 		defer tempData.deinit(main.stackAllocator);
 		while (commands.popBack()) |_cmd| {
 			var cmd = _cmd;
 			cmd.undo();
 			tempData.append(main.stackAllocator, cmd);
 		}
-		if (tempData.popOrNull()) |_cmd| {
-			var cmd = _cmd;
-			var reader = BinaryReader.init(&.{});
-			cmd.finalize(main.globalAllocator, .client, &reader) catch |err| {
-				std.log.err("Got error while cleaning rejected inventory command: {s}", .{@errorName(err)});
-			};
-		}
-		while (tempData.popOrNull()) |_cmd| {
-			var cmd = _cmd;
-			cmd.do(main.globalAllocator, .client, null, main.game.Player.gamemode.raw) catch unreachable;
-			commands.pushBack(cmd);
-		}
-	}
 
-	pub fn receiveSyncOperation(reader: *BinaryReader) !void {
-		mutex.lock();
-		defer mutex.unlock();
-		var tempData: main.List(Command) = .empty;
-		defer tempData.deinit(main.stackAllocator);
-		while (commands.popBack()) |_cmd| {
-			var cmd = _cmd;
-			cmd.undo();
-			tempData.append(main.stackAllocator, cmd);
+		for (syncCommands.items) |sync| {
+			defer sync.deinit();
+			var reader = BinaryReader.init(sync.data);
+
+			switch (sync.typ) {
+				.confirmation => {
+					if (tempData.popOrNull()) |_cmd| {
+						var cmd = _cmd;
+						cmd.do(main.globalAllocator, .client, null, main.game.Player.gamemode.raw) catch unreachable;
+						try cmd.finalize(main.globalAllocator, .client, &reader);
+					} else {
+						std.log.err("Received unexpected confirmation sync. Disconnecting", .{});
+						return error.Invalid;
+					}
+				},
+				.failure => {
+					if (tempData.popOrNull()) |cmd| {
+						try cmd.finalize(main.globalAllocator, .client, &reader);
+					} else {
+						std.log.err("Received unexpected failure sync. Disconnecting", .{});
+						return error.Invalid;
+					}
+				},
+				.sync => {
+					try Command.SyncOperation.executeFromData(&reader);
+				},
+			}
 		}
-		try Command.SyncOperation.executeFromData(reader);
+		syncCommands.clearRetainingCapacity();
+
 		while (tempData.popOrNull()) |_cmd| {
 			var cmd = _cmd;
 			cmd.do(main.globalAllocator, .client, null, main.game.Player.gamemode.raw) catch unreachable;
@@ -621,6 +644,7 @@ pub const Command = struct { // MARK: Command
 					info.dest.inv.update();
 				},
 				.moveToBag => |info| {
+					if (info.amount == 0) continue;
 					const item = info.dest.peek(0).item;
 					std.debug.assert(std.meta.eql(info.source.ref().item, item) or info.source.ref().item == .null);